Browsing by Author "Yue, Xinan"
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Item Restricted Modeling the relationship between E × B vertical drift and the time rate of change of hmF2 (ΔhmF2/Δt) over the magnetic equator(American Geophysical Union, 2008-03-13) Yue, Xinan; Wan, Weixing; Lei, Jiuhou; Liu, L.A middle and low latitude ionospheric model is used to model the relationship between E × B vertical drift velocity and time rate of change of hmF2 (ΔhmF2/Δt) over the magnetic equator. F107 (10.7 cm solar radiation flux) is chosen to be equal to 100, 150, and 200 to represent low, middle, and high solar activities, respectively, and Ap is equal to 1 to represent quiet geomagnetic activity. Our simulations show that hmF2 derived vertical drifts over the magnetic equator are in good agreement with the E × B vertical drift imposed in the model during 0600–0730 and 1700–2100 LT. This is consistent with previous comparisons between vertical drift velocities derived from ionosonde, Jicamarca incoherent scatter radar, and AE‐E observations well. However, the amplitudes of hmF2 derived drift are smaller than the given drift velocities during other local times. During disturbed conditions, the variations of hmF2 can be used to determine the occurrence of intense electric field disturbance.Item Restricted Unusually long lasting multiple penetration of interplanetary electric field to equatorial ionosphere under oscillating IMF Bz(American Geophysical Union, 2008-01-17) Wei, Yong; Hong, Minghua; Wan, Weixing; Du, Aimin; Lei, Jiuhou; Zhao, Biqiang; Wang, Wenbin; Ren, Zhipeng; Yue, XinanDuring November 11–16, 2003, the interplanetary magnetic field (IMF) Bz oscillated between northward and southward directions, which suggests discontinuous magnetic reconnection associated with the multiple pulses‐like reconnection electric field. The Jicamarca incoherent scatter radar (ISR) measurements of ionospheric zonal electric field showed similar fluctuations during this period. The high correlation coefficient of 0.71 between the reconnection electric field and equatorial zonal electric field during 125 hours suggests that the interplanetary electric field (IEF) pulsively penetrated into the equatorial ionosphere due to the discontinuous magnetic reconnection. It is implied that the short lifetime (<3 hours) dawn‐dusk IEF pulses can penetrate into ionosphere without shielding, in other words, they may exhibit the “shielding immunity”. The averaged penetration efficiency is about 0.136 and highly local time‐dependent. Furthermore, the intense AU and AL indices imply that the multiple electric field penetration is associated with a “High‐Intensity Long‐Duration Continuous AE Activity (HILDCAA).